LIGHT SOURCE DEVICE FOR TWO-BEAM SCANNING, OPTICAL SCANNING APPARATUS HAVING LIGHT SOURCE DEVICE FOR TWO-BEAM SCANNING, AND IMAGE FORMING APPARATUS HAVING OPTICAL SCANNING APPARATUS

摘要

PPROBLEM TO BE SOLVED: To provide a light source device for two-beam scanning capable of reducing focus position variation of a beam spot on a face to be scanned due to temperature change. PSOLUTION: The light source device for two-beam scanning 10 has: two laser diode elements 1 and 2 arranged by mutually spacing a prescribed distance; two synthetic resin-made coupling lenses 3 and 4 for converting beams B1 and B2 emitted from the laser diode elements 1 and 2 respectively into parallel light; and a composed prism member 5a for making a composed beam B3 by composing the beams B1 and B2 converted into the parallel light. In addition, diffractive face parts 3a and 4a are provided on the incident faces of coupling lenses 3 and 4. The diffractive face parts 3a and 4a are set so that the focus position variation of the beam spot due to power variation caused by the temperature change of the laser diode elements 1 and 2 and the coupling lenses 3 and 4 are made substantially zero. PCOPYRIGHT: (C)2008,JPO&INPIT